In a clinician's view, best medical practice has two distinct meanings in a tax-funded health system: optimal management as expected by the individual patient; or, the best possible within the economic limits dictated by the society. Based on this viewpoint, this article represents an oncologist's perspective on the meaning of best medical practice in the management of patients suffering from cancer, the extent to which it is achieved in the UK health system, and how far some of the present deficiencies may be overcome. There is urgent need for medical audit in the management of cancer patients in the UK because the traditional clinical freedom of doctors can lead to wide variations in management without corresponding differences in outcome as measured by benefit to the patient. We need consensus by physicians on the guidelines for optimal management of different types of cancer at various stages, both to avoid overtreatment of the individual patient and also to direct scarce resources to their most effective use. Physicians also need to agree on guidelines for giving priority to one patient over another when resources are limited, and such criteria need to be approved by society at large. The public must accept that in a non-explicit rationing system, each individual competes with every other. In the case of even more difficult ethical choices, a multidisciplinary national committee is required to advise on decision-making and its views need to be debated by the general public.